Lacerta 1.25" Herschel Wedge (Prism only)

Product category: Product brand: Lacerta
Lacerta 1.25" Herschel Wedge (Prism only)

Lacerta 1.25" Herschel Wedge (Prism only)

Price 129,00 €

Why Brewster Angle?

The Lacerta 1.25 "Herschel prism with Brewster angle has some advantages over 90 degree prisms. Since the polarization at Brewster angles is almost 100%, the Lacerta Herschel prism with the mandatory ND3 neutral density filter AND with an additional polar filter enables practically full light attenuation - in reality a dimming range between ND4.07 and 6.37 - mostly even more. Without a polar filter, the Herschel prism works at the lowest light attenuation (ND4.07) and can thus be used for photography. With the "traditional" 90 degree Herschel prisms, this value is only between 4.24 and 5.00.

The visual perception at different neutral densities is shown in the picture below. It is easy to see that the granulation in traditional Herschel prisms can only be observed well with an additional THIRD filter (ND3 and polarizing filter are required!). Herschel prisms with Brewster angle do not need an additional filter because the dimming range is continuously possible up to ND6.37!

How do you use the 1.25 "Herschel prism?
- The ND3 filter and the polarizing filter are simply screwed into the eyepiece, the overall brightness is adjusted by turning the eyepiece.
- Please note that the optical elements must strictly have the following order: telescope - Herschel prism - ND3 filter - polar filter - additional filter (e.g. UV / IR block or contrast filter of your choice) - eyepiece (or camera)
- When changing the eyepiece, it is essential to ensure that all filters are screwed around and reassembled in the correct order.

Why is the Lacerta Herschel prism open at the bottom?

- The open design allows much better ventilation than other Herschel wedges on the market
- The proportion of scattered light that comes through the opening is negligible against the sun from the telescope
- No shoes will catch fire as no light escapes through the opening

WARNING! The image through the Herschel wedge is relatively bright without an ND3 filter. The Herschel wedge itself only filters 92-95% of sunlight. Because of this, an ND3 filter is mandatory! This filter is included in the ready-to-use package.

WARNING! Do not use the Herschel wedge with Newtonian, Maksutov or Schmidt-Cassegrain telescopes. The heat can damage the internal parts in these telescopes.

Light path:

1.25 "version: 61mm from T2 to T2


1.25 "version: 308g

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Terms and conditions

These terms and conditions are valid from November 7th, 2020.

Contact information

Astro Art Finland
Sinirinnankatu 18
FI-50190 Mikkeli

Telephone: +358442778923
VAT Number: FI32234856

Products are sold for private customers over 18 years of age. Prices include VAT. The prices are subject to change.


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You can use the following information to contact our customer service:

Astro Art Finland
Sinirinnankatu 18
FI-50190 Mikkeli

Telephone: +358442778923
VAT Number: FI32234856

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Delivery time

Our most common delivery times to Finland vary depending on the product and delivery method in question. Exceptions to delivery times are stated. We will notify you about the possible delays right after your order.

We are not responsible for delays caused by force majeure or indirect losses caused by delays. The online store will inform about exceptional delivery times on the website.


All of our products have at least a 1-year warranty by the manufacturer. Warranty-related issues can be dealt either directly with the manufacturer or with Astro Art Store. 

Warranty does not apply to faults that have been caused by:

a) incorrect maintenance, lack of maintenance, or lack of calibration

b) software, parts, or equipment that have not been delivered by Astro Art Store

c) unauthorized modifications or misuse of the product

Return conditions

You have the right to cancel this agreement within 14 days without declaring the reason. The deadline for canceling this agreement ends 14 days after you have received the last shipment of your order. If the product is downloaded, the deadline for canceling this agreement is 14 days after you have downloaded the product.

To use your right to cancel, you need to send us an unambiguous notification of your decision (for example by phone or by email). You can also use our printable return form, but it is not required. To comply with the 14-day deadline you need to send the notification before the deadline.

Use the following contact information to send the notification:

Astro Art Finland
Sinirinnankatu 18
FI-50190 Mikkeli

Telephone: +358442778923
VAT Number: FI32234856

Effects of canceling your order

If you decide to cancel this agreement, we will return your payment in full, including the shipping costs (only the amount of the cheapest available shipping method). The payment will be returned without a delay, and within 14 days after you have received the cancellation confirmation.

Return fees are on the responsibility of the customer. The items must be returned to the address of Astro Art Finland with the same method as they have been delivered to the customer. 

We will return the payment by using the same payment method as the original payment, unless both parties agree otherwise. The payment is returned in a way that the you will not get any extra fees.

You must send the items back without a delay and within 7 days of receiving the cancellation confirmation. The deadline has been complied with, if you send the items back before the 7-day deadline.

You are only responsible for such decrease in value of the items that is not caused by handling that necessary to test for operation, features, or functionality of the items.

Unredeemed package

Failure to redeem your delivery is not the same as returning or canceling your order. We will charge a fee for unredeemed orders that have not been canceled according to return conditions.

Problematic situations

If the item has been lost or damaged during delivery or it does not correspond to your order, you need to use our contact information to inform us within 14 days by mail, email or by phone. The contact information can be found in "Return conditions". If the package has clearly been damaged during shipping, you need to inform the delivery company immediately.